Fuel storage tanks, as well as other types of tanks and containers, are often filled from tank trucks and other sources of liquid. Typically, the tank truck has a filler hose which is connected to a twist lock fitting mounted to the upper end of a drop tube housed within the tank. Drop tubes are used to reduce or eliminate static electricity which could be created if the liquid were merely pumped directly into the tank through an open port at the top of the tank. The filling of the tank can be either gravity-fed from the fuel tank truck or it can be assisted by a pump. In either event, it is important that the tank not be overfilled. One way to do this is through the use of an automatic shut-off valve assembly. Such assemblies typically include a float within the tank which actuates some sort of valve element along the flow path from the end of the supply hose to the bottom of the drop tube.
One type of conventional shut-off valve assembly includes a flapper valve housed within the drop tube; the flapper valve is coupled to a float positioned on the outside of the drop tube. An example of this type sold by EBW of Muskegon, Mich. as No. 9010 Auto Limiter. Another type if drop tube shut-off valve uses a float within the tank to control a valve assembly positioned external on the tank between the top of the full pipe and the filler hose. An example of this type is sold by Clay and Bailey Mfg. Co. of Kansas City, Mo. as the MINO Filling Limiter.
What is lacking in the art is a truly simply, relatively inexpensive and straightforward shut-off valve assembly for use with tanks having a drop tube.